Valve assembly

ABSTRACT

A non-riser valve assembly 30 includes a bonnet or housing 32, a bushing 34, a stem 36, a washer 38 and a stop 40. The assembly 30 further includes a coupling 42, a rotatable or movable disk 44, a fixed disk 46 and a bottom seal 48. In assembly, the bushing 34 and the stem 36 are located within an opening 50 of the housing 32 with the bushing being located between the housing and the stem. One of the stem 36 extends from one end of the opening 50 and the stop 40 is removably attached to the stem to limit the rotational movement of the stem within the housing. The coupling 42 is located in the opening 50 of the housing 32 and is in driving engagement with the opposite end of the stem 36. The movable disk 44 is located with the opening 50 and is coupled to the coupling 42 for rotation therewith. The fixed disk 46 is attached to the housing 32 within the opening 50 and is formed with a surface 224 which is in water-sealing engagement with a surface 162 of the movable disk 44. The disks 44 and 46 are formed with passages 164 and 218, respectively, the relative positioning of which is controlled by rotation of the stem 36 to control the flow of water therethrough.

BACKGROUND OF THE INVENTION

This invention relates to a valve assembly and particularly relates to anon-rise valve assembly.

Valve assemblies which are used with showers and tub arrangements mayuse a two-handle system for controlling the selective flow of hot andcold water. In such a system, the hot and cold handles are connected torespective valve assemblies which are located within an in-wall body.The in-wall body is typically cast or formed as an integral unit whichincludes two spaced end bodies containing the valve assemblies, a centerbody between the end bodies, and in-wall conduits which couple thecenter body to the end bodies. The center body is coupled to ashowerhead and a tub spout through linking conduits.

In the two-handle system as described above, hot and cold water issupplied to respective end bodies where, upon selective control of thevalve assemblies, water flows through the valve assemblies. The watercontinues to flow through the in-wall conduits, the center body; andthrough either the showerhead or the spout, and the linking conduitcoupled thereto, depending on the selective position of a fluid diverterassociated with the system.

In one type of valve assembly which has been used in the past, andcontinues to be used today, a washer is assembled at the base of a stemof the valve. The stem is threadedly mounted within a housing or bonnetof the valve so that, upon rotation of the stem, the stem is movedaxially to either move the washer into sealing engagement with a seat ofthe housing to close the valve or to move the washer away from the seatto open the valve. This is referred to as a riser type of valve becausethe stem moves axially out of the housing or bonnet.

Another type of valve used in a two-handle faucet is a non-rise valveand employs two ceramic disks which are always in interfacing engagementand which are formed with openings to facilitate the flow of watertherethrough. When the openings of the disks are not aligned in anyrespect, the valve is closed to prevent the flow of water therethrough.When the valve handle and associated stem are turned, one of the diskswhich is attached to the stem is rotated relative to the other diskwhile the two disks remain in interfacing engagement. Eventually, theopenings of the disks are aligned and water is allowed to flow throughthe openings and out of the spout. In this type of valve, the stem ofthe valve does not move axially as the valve is opened, in contrast tothe valve with the threadedly mounted stem noted above. A few examplesof the many valves of the ceramic type are disclosed in U.S. Pat. Nos3,780,758; 3,831,621 and 5,174,324.

In a two-handle valving arrangement of the type described above, thevalves typically are located in spaced relation to each other with onevalve referred to as the left side valve for controlling the supply ofhot water, and the other valve referred to as the right side valve forcontrolling the supply of cold water.

Generally, in ceramic valves of this type, the stem is freely rotatablewithin the bonnet in a clockwise direction and a counterclockwisedirection. Therefore, a given design of a ceramic valve could be used onboth sides of a two-handle faucet, that is as a right side valve and asa left side valve to provide the turning direction typically associatedwith a cold water valve on the right side of the faucet and a hot watervalve on the left side of the faucet. However, a turning limit stop mustbe employed to limit the turning of the valve in each direction toone-half of a full turn. In order to take advantage of the premise ofusing ceramic valves of a common design in both valves of a shower andtub arrangement, a reversible stop is used with each valve to limit theturning of the stem in one direction or the other depending on whetherthe valve is being used on the right side or the left side of thefaucet. An example of a reversible stop which is used for this purposeis disclosed in U.S. Pat. No. 3,831,621.

When assembling the components of a ceramic valve of the type notedabove, it is critical that the components be assembled in the properrelationship and orientation, otherwise the valve will not function inthe manner intended. Typically, the components of the valves areassembled in a factory to form the valves. During the assembly process,the reversible stops are assembled so that each valve is either a hotwater or a cold water valve and the valves are segregated accordingly. Ahot water valve is then assembled into one of the pair of spaced endbodies on opposite ends of the in-wall body which is to the left of acenter body thereof. A cold water valve is then assembled into the otherend body which is to the right of the center body. The in-wall body withthe valve assemblies is packaged and shipped, eventually, to aninstallation site where it is installed in a plumbing system. Thus, itis important that some provision be made to insure that the reversiblestop is assembled in the proper manner to provide a hot water or a coldwater valve so that, when that valve is assembled with the in-wall body,it is assembled in the appropriate end body thereof.

During the period immediately following the assembly of the componentsof the valve, the valve is transported within the factory to variousstations for further processing. Also, individual valves may be packagedand sold as replacement units for installation with existing, previouslyinstalled shower and tub arrangements.

Current techniques and facilities for retaining the assembled reversiblestop with the valve assembly, typically include elements which requiretools to insert and remove the stop. This requires that the installercarry appropriate tools necessary for such actions. In the factory aswell as at the installation site, provision must be made for retainingthe reversible stop of the valve in assembly during periods of handling,shipment, storage, and ultimate assembly with other elements of theshower and tub arrangement at the factory or installation sites. Inaddition, provision must be made for facilitating easy removal of thestop.

With respect to the valves which are installed as replacements inexisting shower and tub arrangements, provision must be made to insurethat, when replacing a hot water valve or a cold water valve, thereversible stop is assembled in the appropriate manner for the valve tofunction accordingly. Of course, the same provision must be made toinsure the appropriate assembly in the factory.

At times, a homeowner may wish to convert a shower and tub arrangementfrom a knob-handle unit to a lever-handle unit. In this instance, onlythe knobs are removed and replaced by levers. When only knobs are used,the reversible stops are situated within the valve assembly in a precisemanner to accommodate the conventional turning for the hot and coldwater valves in the same direction, that is clockwise to close for boththe hot and cold water valves. When levers are used, the hot and coldlevers extend in generally opposite directions from each other when thevalve is fully closed. When opening the lever-operated valves, the hotand cold valves are conventionally turned in opposite directions. Forexample, the cold lever is turned in a clockwise direction and the hotlever is turned in a counterclockwise direction to open the valve. Thus,to open the cold water valve for the knob assembly, the knob is turnedin a counterclockwise direction, while to open the cold water valve forthe lever assembly, the lever is turned in a counterclockwise direction.Therefore, provision must be made for easily reversing the cold watervalve assembly when converting from a knob assembly to a lever assembly,or vice versa, and for insuring that the reversible stop is properlyoriented to accommodate such change.

As noted, ceramic valves include two ceramic disks which are always ininterfacing contact. Each disk is formed with an opening where, whenaligned at least partially with the opening of the other disk, waterwill flow through the openings of the two disks. If the openings of thedisks are designed to allow large amounts of water to flow when thevalve is turned on or off, loud and undesirable noises, known as "waterhammering," can develop because large amounts of water are suddenlytrying to flow or cease flowing in a relatively short period of time.Also, the configurations of the openings can affect the temperature andflow resolution of the water mix which is passing through the openings.Thus, provision must be made for essentially eliminating the waterhammering noise and for providing an excellent temperature and waterflow resolution.

In valves of this type, the stem is rotatable within a bore of thebonnet. Due to the structural nature of these two elements, there is atendency for the elements to wobble relative to each other. Also, thereis a tendency for the elements to bind. Thus, provision must be made forminimizing any back lash or wobbling between the stem and the bonnetwhile insuring that the stem rotates relative to the bonnet withrelative ease.

In view of the above-noted provisions, there is a need for a valveassembly which can be assembled in an efficient manner while insuringthat a reversible stop thereof is properly assembled for the valve tofunction in the intended manner. In addition, there is a need forfacilities which provide for the easy assembly and disassembly of thereversible stop. Further, there is a need for controlling the water flowthrough openings in the ceramic disks to facilitate avoidance of anyhammering noise and to insure excellent temperature and water flowresolution. Also, there is a need for facility to minimize wobblingbetween the stem and the bonnet and to insure that the stem moves withease relative to the bonnet.

SUMMARY OF THE INVENTION

In view of the foregoing needs, it is an object of this invention toprovide a valve assembly having facility for insuring that components ofthe valve are assembled in an intended manner for proper operationthereof.

Another object of this invention is to provide a valve assembly havingfacility for insuring that components of the valve assembly may beeasily assembled and disassembled.

Still another object of the invention is to provide for easy andcomfortable operation of the valve assembly while providing necessarystability between moving parts thereof.

A further object of the invention is to provide flow passages whichprovide for excellent water temperature and water flow resolution whileessentially preventing water hammering.

With these and other objects in mind, this invention contemplates avalve assembly which includes a housing and a stem mounted within thehousing for free rotation relative thereto. A first end of the stemextends from a first opening of the housing. A first fluid-flow valveelement is located within the housing and is coupled to a second end ofthe stem for rotation therewith. The first valve element is formed witha surface which is in facing engagement with a first surface of a secondfluid-flow valve element fixedly attached within and to the housingadjacent a second end of the housing. A stop element is assembled on thefirst end of the stem and is retained the assembled position bycomplementary structure formed on the stem and the stop element.

This invention further contemplates a valve assembly which includes ahousing and a stem mounted within the housing for free rotation relativethereto. A first fluid-flow valve element is located within the housingand is coupled to an end of the stem for rotation therewith. The firstvalve element is formed with a surface which is in facing engagementwith a surface of a second fluid-flow valve element fixedly attachedwithin and to the housing adjacent a second end of the housing. Thefirst and second valve elements are each formed with fluid flow openingswhich, when aligned, will allow fluid to flow therethrough. The openingof the first valve element is formed to restrict the flow of fluidinitially to a limited level and thereafter to allow the flow level togradually increase to full level.

Still another object of this invention contemplates a valve assemblywhich includes a housing and a stem mounted within the housing for freerotation relative thereto. An intermediate element is interposed betweenthe housing and the stem to enhance the stable rotation between thehousing and the stem.

Other objects, features and advantages of the present invention willbecome more fully apparent from the following detailed description ofthe preferred embodiment, the appended claims and the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is an exploded perspective view showing a valve assembly inaccordance with certain principles of the invention;

FIG. 2 is a side view showing structural features of the valve assemblyof FIG. 1 in accordance with certain principles of the invention;

FIG. 3 is a side view rotated, ninety degrees from the side view of FIG.2, showing structural features of the valve assembly of FIG. 1 inaccordance with certain principles of the invention;

FIG. 4 is a perspective view showing structural features of a housing orbonnet of the valve assembly of FIG. 1 in accordance with certainprinciples of the invention;

FIG. 5 is a sectional view showing the housing or bonnet of FIG. 4 inaccordance with certain principles of the invention;

FIG. 6 is a side view showing structural features of a stem of the;valve assembly of FIG. 1 in accordance with certain principles of theinvention;

FIG. 7 is a sectional view showing the stem of FIG. 6 in accordance withcertain principles of the invention;

FIG. 8 is a top view showing structural features of one end of acoupling of the valve assembly of FIG. 1;

FIG. 9 is a side view showing structural features of the coupling ofFIG. 8;

FIG. 10 is a bottom view showing structural features of the coupling ofFIG. 8;

FIG. 11 is a side view, rotated ninety degrees from the side view ofFIG. 9, showing structural features of the coupling of FIG. 8;

FIG. 12 is a bottom view of a first embodiment of a first valve elementof the valve assembly of FIG. 1 showing structural features inaccordance with certain principles of the invention;

FIG. 13 is a top view of the first valve element of FIG. 12 showingstructural features in accordance with certain principles of theinvention;

FIG. 14 is a perspective view showing structural features of the firstvalve element of FIG. 12 in accordance with certain principles of theinvention;

FIG. 15 is a bottom view showing structural features of a secondembodiment of a first valve element in accordance with certainprinciples of the invention;

FIG. 16 is a sectional view taken along line 16--16 of FIG. 15 showingsome of the structural features of the valve element of FIG. 15;

FIG. 17 is a bottom view showing structural features of a thirdembodiment of a first valve element in accordance of certain principlesof the invention;

FIG. 18 is a sectional view taken along line 18--18 of FIG. 17 showingsome of the structural features of the valve element of FIG. 17;

FIG. 19 is a perspective view showing structural features of the valveelement of FIGS. 17 and 18;

FIG. 20 is bottom view showing structural features of a second valveelement of the valve assembly of FIG. 1 in accordance with certainprinciples of the invention;

FIG. 21 is a perspective view showing structural features of the secondvalve element of FIG. 20 in accordance with certain principles of theinvention;

FIG. 22 is a sectional view showing structural features of a bottom sealof the valve assembly of FIG. 1;

FIG. 23 is a perspective view showing structural features of a bushingof the valve assembly of FIG. 1 in accordance with certain principles ofthe invention;

FIG. 24 is a side view showing structural features of the bushing ofFIG. 23 in accordance with certain principles of the invention;

FIG. 25 is a perspective view showing structural features of a stop ofthe valve assembly of FIG. 1 in accordance with certain principles ofthe invention;

FIG. 26 is an end view showing structural features of the stop of FIG.25 in accordance with certain principles of the invention;

FIG. 27 is sectional view showing structural features of the stop ofFIG. 25 in accordance with certain features of the invention;

FIG. 28 is a partial bottom view of the first embodiment of the firstvalve element of FIG. 12 showing dimensional features of the first valveelement in accordance with certain principles of the invention;

FIG. 29 is a diagrammatical view showing the relative positions of thefirst valve element of FIG. 12 and the second valve element of FIG. 20when the valve assembly of FIG. 1 is fully closed which represents azero degrees position;

FIG. 30 is a diagrammatical view showing the relative positions of thefirst valve element of FIG. 12 and the second valve element of FIG. 20when the valve assembly of FIG. 1 is opened by thirty degrees;

FIG. 31 is a diagrammatical view showing the relative positions of thefirst valve element of FIG. 12 and the second valve element of FIG. 20when the valve assembly of FIG. 1 is opened by ninety degrees; and

FIG. 32 is a diagrammatical view showing the relative positions of thefirst valve element of FIG. 12 and the second valve element of FIG. 20when the valve assembly of FIG. 1 is opened by one-hundred and eightydegrees or the fully open position of the valve assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENT

As shown in FIG. 1, a non-riser valve assembly 30 includes a bonnet orhousing 32, a bushing 34, a stem 36, a washer 38 and a stop 40. Theassembly 30 further includes a coupling 42, a rotating or movable disk44, a fixed disk 46 and a bottom seal 48. A valve of this type can beused with a two-handle faucet (not shown) for controlling the separateselection of the volume of hot and cold water to be supplied to, mixedin and passed through the faucet. Also, the valve assembly 30 has beendesigned for use with a faucet system which allows a half-turn, that is,a turn of one-hundred and eighty degrees, of the stem 36 of each valveassembly within defined limits.

Referring to FIGS. 2, 3 and 5, the housing 32, which is composed ofbrass, is formed with an axial bore 50 which extends through the housingfrom a top end 52 to a bottom 54 thereof. As shown clearly in FIG. 5,three spaced shoulders 55, 56 and 57 are formed laterally within thebore 50 and divide the bore into four cylindrical chambers 58, 59, 60and 62. The housing 32 is also formed with a stop wall 64 extendingupward from an upper surface 66 at the top end 52 of the housing.Opposite ends of the stop wall 64 form stop surfaces 68 and 70 (FIG. 1).The housing 32 is also formed with a flange 72 which extends radiallyfrom an intermediate external portion of the housing to form a shoulder74 on the underside of the flange. A threaded section 76 is formed onthe external surface of the housing 32 below the flange 72. A pair ofwindows 78 and 80 (FIGS. 1 and 4) are formed through a cylindrical sidewall 82 of the housing 32 near the bottom end 54 thereof. As shown inFIGS. 1, 3, 4 and 5, a pair of opposed vertical slots 84 and 86 areformed within bore 50 of the housing 32 and extend from the bottom 54 ofthe housing to a central portion of each of the windows 78 and 80.

Referring to FIGS. 6 and 7, the stem 36, which is composed of brass, isformed with a base 88 and a stem element 90 extending upward from thebase. The base 88 is formed in a circular shape with a through slot 92formed in an undersurface 94 thereof. It is noted that the slot 92 isoffset slightly from the axis of the stem 36 as shown in FIG. 6 and,therefore, is not formed diametrically across the undersurface 94. Thestem element 90 is formed with a pair of spaced circular bands 96 and 98at the bottom and intermediate portions thereof which are formed withthe same diameter. As shown in FIGS. 1 and 6, a first set of spacedsplines 100 are formed on the stem element 90 immediately above the band96. Uniformly wide spaces 101 are formed between all adjacent splines100 except for a single pair of adjacent splines which are spaced toform a much wider space 103 (FIG. 1) therebetween. Each of the splines100 extend radially outward from the stem element 90 and are parallel tothe axis of the stem 36. Each of the splines 100 is formed with a lower,rectangularly shaped section 102, an intermediate section including awide-angle "V" shaped notch 104 and a small rectangular portion 106.Each of the splines 100 is further formed with an upper section 108which tapers inward and upward from portion 106 toward the axis of thestem 36. A second set of splines 110 is formed on the stem element 90 atthe top thereof with spaces 111 formed between adjacent splines 110.Each of the set of splines 100 extend a uniform radial distance from theaxis of the stem 36 which is greater than the extended uniform radialdistance from the axis of each of the set of splines 110. As shown inFIGS. 1 and 7, a threaded opening 107 is formed in a top surface 109 ofthe stem element 90.

As shown in FIG. 1, the coupling 42, which is composed of a plasticmaterial, is formed with a cylindrical intermediate body 112 which, asshown in FIGS. 9 and 11, is closed at an upper end 113 thereof and openat a bottom end 115 thereof. The body 112 is formed with an open chamber114 which extends from the open bottom end 115 to the closed upper end113 thereof. The exterior of the upper end 113 of the coupling 42 isformed with a circular flange 116 which is integrally formed with andextends radially outward from the top of the body 112. The bottom end115 of the coupling 42 is formed with a flared section 118 (FIG. 11)which is located about the opening at the bottom of the chamber 114. Asecond circular flange 120 is formed about the body 112 spaced slightlyfrom the flange 116 to form an annular groove 121 (FIGS. 2, 3, 9 and 11)therebetween for receiving a rubber O-ring 123 (FIGS. 1, 2 and 3). Apair of ribs 122 are formed on opposite sides of the body 112, as shownin FIGS. 1 and 9, between the flange 116 and the flared section 118 andare parallel to the axis of the coupling 42.

The ribs 122 separate the exterior surface of the body 112 between theflange 116 and the flared section 118 into two sections 124 and 126(FIG. 1). As shown in FIG. 11, the body 112 is formed with four holes128 which extend from the chamber 114 to the exterior of the coupling42. The holes 128 are separated into two pairs of holes, two of whichare open at section 124 and the other two open at section 126 of thecoupling 42. As shown in FIGS. 8 and 9, a lug 130 extends in an axialdirection from the upper end 113 of the coupling 42. The lug 130 isformed with rounded ends and with four crusher ribs 132 on oppositesides of the lug. A moat 134 is formed around the base of the lug 130.Also, the lug 130 is offset from the axis of the coupler 42.

As shown in FIGS. 9, 10 and 11, the chamber 114 of the coupling 42 isopen at the bottom end 115 and the coupling is formed with four spacedwalls 136, 138, 140 and 142 of different circumferential lengths whichextend in an axial direction from a bottom surface 143 at the bottomend. Spaces 144, 146, 148 and 150 are formed between respective pairs ofthe walls 136, 138, 140 and 142 as shown in FIG. 10 and are spacedradially from each other in a prescribed arrangement as illustrated. Forexample, as viewed in FIG. 10, space 144 is located about ninety degreesin a clockwise direction from space 150, space 146 is located aboutseventy degrees in a clockwise direction from space 144 and space 148 islocated about one hundred and ten degrees in a counterclockwisedirection from space 150.

As shown in FIG. 1, a pair of windows 152 are formed through the section126 of the coupler 42 adjacent the bottom end 115 and are separated by astrut 154. As shown in FIG. 9, an identical pair of windows 156,separated by a strut 158, are formed through the section 124 directlyopposite the windows 152 and in the same manner. The windows 152 and 156allow open communication between the outer portions of the coupler 42adjacent the sections 126 and 124, respectively, and the chamber 114.

Referring now to FIG. 12, the movable disk 44, which is composed of aceramic material, is formed generally in a circular configuration havinga sidewall 160, a bottom surface 162 and a passage 164 which extendsthrough the disk. The passage 164 is formed with a contoured wall 166 ofa prescribed configuration which includes an outboard wall section 168spaced inward from the sidewall 160 and which follows the circularconfiguration thereof. The wall 166 further includes a small half-circlewall section 170 having two ends, one end of which is formed and joinswith a respective end of the wall section 168. The wall 166 alsoincludes a slightly curving wall section 171 which extends from theother of the two ends of the wall section 168. The wall section 170 isspaced from an adjacent portion of the wall section 168 and graduallyextends inward toward the axis of the disk 44 to form a slightlywidening but narrow channel 172 between the section 170 and the adjacentportion of the section 168. The wall section 171 and the oppositeportion of the wall section 168 form an inside wall section and anoutside wall section, respectively, of the channel 172 while the wallsection 170 forms a base of the channel. The wall section 170 extendsfor a prescribed distance and then joins with one of two ends of aconvex wall section 174. A convex linking wall section 176 joins andextends from the other of the two ends of the wall section 174 to ajuncture where the section 176 joins with a deep concave wall section178 which is spaced considerably from an opposite portion of the wallsection 168. The convex wall projection 174 and the linking wall section176 combine to form a combined convex wall section which extends betweenits juncture with the curving wall section 171 and the concave wallsection 178.

In similar fashion, the other end of the wall section 168 joins withportions of the wall 166 formed by a half-circular wall section orchannel base 180, a slightly curving or channel inside wall section 182,a convex wall section 184 and a linking wall section 186 which joinswith the other end of the concave wall section 178 to complete the wall166. A widening but narrow channel 188 is formed between the section 182and an adjacent portion of the wall section 168 in the same manner asthe channel 172. It is noted that, while the wall 166 is formed in thecontour as illustrated in FIG. 12, the portion of the passage 164 abovethe horizontal centerline of the disk 44 is symmetrical with the portionof the passage below the centerlines. It is also noted that theconfiguration of the passage 164 as defined by the wall 166 is aprescribed configuration which has been precisely designed to providefor the efficient and acoustically friendly flow of water therethroughduring various stages of use of the valve assembly 30 from a fully "off"condition to a fully "on" condition.

A large open bay 274 is formed by a large portion of the passage 164.The bay 274 is defined by a central portion of the wall section 168(exclusive of the portions defining the channels 172 and 188), theconvex wall sections 174 and 184, the linking wall sections 176 and 186,the concave wall section 178 and an open mouth of each of the channels.In this manner, the bay 274 is in communication with the narrow channels172 and 188.

Referring to FIGS. 13 and 14, the disk 44 is formed with a top surface189 which is contiguous with the passage 164. Four notches 190, 192, 194and 196 are formed spatially in the top surface 189 and in thecontiguous portions of the sidewall 160 resulting in the formation offour radial fingers 198, 200, 202 and 204. The depth of each of thenotches 190, 192, 194 and 196, and consequently the fingers 198, 200,202 and 204, is about one-half the thickness of the disk 44. It is notedthat the radial arrangement of the fingers 198, 200, 202 and 204 is thesame as the radial arrangement of the spaces 144, 146, 148 and 158 ofthe coupler 42 (FIG. 10).

A second embodiment of the movable disk of the valve assembly 30 isillustrated in FIGS. 15 and 16 and is very similar to the disk 44 of thefirst embodiment and is also composed of a ceramic material. In order todistinguish between the first and second embodiments, the numeral "44a"will identify the second embodiment. The numerals assigned above to thestructural elements of the first embodiment of the disk 44 asillustrated in FIGS. 12, 13 and 14, which are common to the structure ofthe second embodiment, will be used in the illustrations of the secondembodiment of the disk 44a of FIGS. 15 and 16, with additional numeralsbeing used to define the differences between the two embodiments.

As viewed from the bottom of the disk 44a in FIG. 15, a first step 206is formed in the portion of the wall 166 which includes the linking wallsection 176 and slight adjacent portions of the convex wall section 174and the concave wall section 178. A similar step 208 is formed in thelinking wall section 186 of the wall 166 and extends slightly toadjacent portions of the convex wall section 184 and the concave wallsection 178. As viewed in FIG. 16, the step 208 is located a very shortinboard distance from the plane of the bottom surface 162 of the disk44a. The step 206 is also located the same distance from the surface162.

A third, and preferred, embodiment of the movable disk of the valveassembly 30 is illustrated in FIGS. 17, 18 and 19 and is very similar tothe disks 44 and 44a of the first and second embodiments, respectively.In order to distinguish between the three embodiments, the numeral "44b"will identify the third embodiment. The numerals above which identifythe structural elements of the first and second embodiments of the disks44 and 44a as illustrated in FIGS. 12 through 16 will be used in theillustrations of the third embodiment of the disk 44b of FIGS. 17, 18and 19 to identify structure common to the three embodiments. Additionalnumerals will be used to define the additional structure of the thirdembodiment of the disk 44b which is also composed of a ceramic material.

As shown in FIGS. 17, 18 and 19, a second step 210 is formed in thelinking wall section 176 of the disk 44b and is spaced from the firststep 208 toward the top surface 189 of the disk 44b. The step 210 isformed generally along the same portion of the wall 166 as the step 208,that is, it extends along the linking wall section 186 and slightly intothe convex wall section 184 and the concave wall section 178. In similarfashion, a second step 212 is formed adjacent the step 206 and is spacedtherefrom in the same manner as the step 210 is spaced from the step208.

Referring now to FIG. 20, the fixed disk 46, which is composed of aceramic material, is formed generally in a circular configuration havinga sidewall 214, a bottom surface 216 and a passage 218 which extendsthrough the disk. The passage 218 is formed generally in a half-circleconfiguration. A pair of locating lugs 220 extend radially outward fromdiametrically opposite portions of the sidewall 214. Grooves 222 areformed in the sidewall 214 adjacent, and on each side of, the base ofeach of the lugs 220. As shown in FIG. 21, the fixed disk 46 is alsoformed with an upper surface 224 which has three arcuate, closed-endgrooves 226, 228 and 230 formed therein.

As shown in FIG. 22, bottom seal 48 is formed in a circular ring-likeconfiguration having generally an oval cross section and is composed ofa rubber material suitable for forming a water seal.

Referring to FIGS. 23 and 24, the bushing 34, which is composed of aplastic material, is formed in the configuration of a cylinder 232 witha flange 234 extending radially from one end thereof. The cylinder 232is formed with a bore 236 extending axially therethrough and a slantedslot 238 in the wall of the cylinder. The slot 238 extends from andthrough one axial end of the cylinder 232 to and through the oppositeaxial end and through the flange 234. Consequently, the slot 238 isformed with two spaced, interfacing walls 240 and 242.

As shown in FIGS. 25 and 26, the stop 40, which is composed of a plasticmaterial, is formed generally with a cylindrical section 244 having anaxial bore 245 formed therethrough. A projection 246 is formed with thesection 244 and extends radially from a portion of a sidewall 248 of thesection. The projection 246 is formed with spaced sidewalls 250 and 251which taper inward from an outboard, convex surface 252. The stop 40 isformed with a first end surface 254 which forms one end of thecylindrical section 244 and the projection 246. A first groove 256 isformed in the end surface 254, radially of the axis of the stop 40 andinto the projection 246 and the cylindrical section 244. A second groove258 is formed in the bottom surface 254, radially of the axis of thestop 40 and into the cylindrical section 244. The first groove 256 isdiametrically aligned with the second groove 258 and the grooves arelocated on opposite sides of the bore 245. As shown in FIG. 1, the stop40 is formed with a second end surface 260 at the end opposite the endsurface 254 which surrounds the bore 245 and extends over the projection246. The projection 246 is also formed with an opening 262 which extendsthrough the projection between the surfaces 254 and 260 as shown in FIG.3.

As viewed in FIGS. 25, 26 and 27, each of a plurality of splines 264 areformed with a prescribed width and extend radially inward from the wallof the bore 245 and extend in an axial direction between the endsurfaces 254 and 260. Each of the splines 264 is spaced equally by aprescribed distance from adjacent splines to form a space 267 betweeneach set of adjacent splines. A wide spline 266, which is wider than theprescribed width and which complements the width of the space 103(FIG. 1) of the stem 36, also extends radially inward from the wall ofthe bore 245 in an axial direction and is spaced from adjacent ones ofthe splines 264 on each side thereof by the prescribed distance. Each offour of the spaces between adjacent splines 264 has a bump or bead 268of relatively short axial length formed therein generally centrallywithin the bore 245.

In one process of assembling the elements of the non-riser valveassembly 30, a lubricant is placed on the outer surface of the stem 36in the area between the spaced bands 96 and 98. Thereafter, the flangeend of the bushing 34 is positioned axially over the splined end of thestem 36 and the bushing is moved over the stem until the flange 234rests on the base 88 of the stem.

Thereafter, the O-ring 123 is placed in the annular groove 121 of thecoupling 42 which is then positioned so that the offset lug 130 thereofis aligned with the offset slot 92 of the stem 36. The lug 130 is thenmoved into the slot 92 where the crusher ribs 132 are disturbed toprovide a firm friction fit of the lug within the slot.

During manufacture of the movable disk 44 and the fixed disk 46, thebottom surface 162 of the movable disk and the upper surface 224 arehighly polished so that the two surfaces, when mated, form a seal toprevent water from leaking from the periphery juncture thereof. Also, bybeing highly polished, the surfaces 162 and 224 allow for easy turningof the valve assembly 30 by a user thereof in a user-friendly manner. Inaddition, the grooves 226, 228 and 230 formed in the upper surface 224of the fixed disk 46 reduces the interfacing surface area between themovable disk 44 and the fixed disk to further provide for easy turningof the movable disk. A small amount of lubricant is placed on theinterfacing surfaces 162 and 224, with some of the lubricant locating inthe grooves 226, 228 and 230, to further enhance the turnability of thevalve assembly 30.

The upper surface 189 of the movable disk 44 is positioned adjacent andaligned axially with the bottom end 115 of the coupling 42 with thefingers 198, 200, 202 and 204 of the movable disk being aligned with thespaces 150, 144, 146 and 148, respectively. The movable disk 44 is thenmoved into assembly with the bottom end 115 of the coupling 42 with thefingers 198, 200, 202 and 204 being located in the spaces 150, 144, 146and 148, respectively, to insure that the movable disk is properlylocated with respect to the coupling. This manner of assembly of themovable disk 44 with the coupling 42 also insures that the movable diskis properly located with respect to the splines 100, and moreparticularly the wide space 103, of the stem 36 by virtue of thepreviously-described offset assembly of the coupling lug 130 with thestem slot 92.

The splined end of the stem 36, with the assembled bushing 34, coupling42 and movable disk 44, are inserted and moved into the axial bore 50 ofthe housing 32 at the bottom end 54 thereof until the flange 234 of thebushing engages shoulder 55 within the bore. At this point, intermediateand lower portions of the stem 36 occupy the chamber 58 and portions ofthe chamber 59. Also, the splines 100 and 110 of the stem 36 have beenextended fully through the bore 50 of the housing 32 and are fullyexposed above the upper surface 66 of the housing. Further, the coupling42 is located within portions of chambers 59 and 60 with the O-ring 123forming a seal against the wall of the chamber 59, and the movable disk44 is located within an intermediate portion of the chamber 60.

Thereafter, with the upper grooved surface 224 of the fixed disk 46facing the bottom end 54 of the housing 32, the disk is axially alignedwith the housing and the lugs 220 of the disk are aligned with the slots84 and 86 of the housing. The fixed disk 46 is then inserted into thechamber 60 of the housing 32 with the lugs 220 passing into the slots 84and 86. Eventually, the upper surface 224 of the fixed disk 46interfaces with and engages the bottom surface 162 of the movable disk44 and the bottom surface of the fixed disk is generally flush pith theshoulder 57 of the housing. The stem 36 is then turned until the passage164 of the movable disk 44 and the passage 218 of the fixed disk 46assume the relative positions illustrated in FIG. 29 to block thepassage 164 whereby the stem and the movable disk are in the fullyclosed position.

The bottom seal 48, which has an outer diameter slightly greater thanthe inner diameter of the housing chamber 62, is inserted into thechamber and against the bottom surface 216 of the fixed disk 46 toessentially retain the assembled components within the housing 32.

The stop 40 is then positioned so that, depending upon whichstem-turning convention is to be used as described below, either thegrooved end surface 254 or the ungrooved end surface 260 of the stop isspaced from but facing the top surface 109 of the stem 36 and so thatthe stop is in axial alignment with the stem 36. Also, the wide spline266 of the stop 40 is aligned with the complementarily wide space 103 ofthe stem 36. The stop 40 is then moved axially onto the stem 36.

As noted above, the outboard ends of the splines 110 extend radiallyfrom the axis of the stem 36 for a distance which is less than theradial distance of the inboard ends of the splines 264 from the axis ofthe stop 40. The splines 264 of the stop 40 are designed to meshultimately with the splines 100 of the stem 36. Since the splines 110extend radially for a distance less than the splines 100 in the mannernoted above, there is sufficient clearance to allow the stop 40 to bemoved axially over and past the splines 110 without interference betweenthe splines 110 and the splines 264.

Eventually, the splines 264 of the stop 40 mesh with the splines 100 ofthe stem 36 with the wide spline 266 being located in the wide space103. As the stop 40 is being assembled onto the splines 100 of the stem36, the four bumps 268 of the stop, snap into the "V" notches 104 ofadjacent splines 100 to effectively lock the stop on top of the stem. Alow level force is required to withdraw the stop 40 from the splines 100of the stem 36 whereby the bumps 268 move out of the "V" notches 104.

When the stop 40 is assembled onto the stem 36, the projection 246 willlocate in either of two positions depending upon the turning conventionwhich has been selected for the subject valve assembly 30. This insuresthat the projection 246 is in position to allow rotation of the stop 40about the axis of the valve assembly 30 between and within the limitsdefined by the stop surfaces 68 and 70 of the stop wall 64 and thespaced sidewalls 250 of the stop in the selected turning convention asdescribed below.

During assembly of the bushing 34 with the stem 36 as described above,and due to the slanted slot 238 of the bushing 34, the bushing expandsslightly to fit snugly around the bands 96 and 98 but is allowed torotate freely relative to the bands and the stem 36 during use of thevalve assembly 30. During this rotational movement, some of theabove-noted lubricant which was heretofore confined to some extentbetween the bushing 34 and the stem 36 will "work" its way through theslot 238 and thereby provide lubricant for surfaces not only between thestem and the bushing but also for the surfaces between the bushing andthe housing 32.

The slanted arrangement of the slot 238 also provides radial structuralintegrity for the bushing 34 during use of the valve assembly 30 byenhancing the radial stiffness of the bushing. For example, if the slot238 was straight in an axial direction from the top to the bottom of thebushing 34, the bushing could have a weakened radial integrity along thestraight column of the slot. By forming the slot 238 on a slant, thereare no top-to-bottom straight sections of the bushing 34 which arecompletely void of the bushing material such as in the above examplewhere the slot is straight and in an axial direction. In fact, for eachtop-to-bottom straight section of the bushing 34 in the vicinity of theslanted slot 238, only that portion of each straight section whichintersects the slanted slot is void of material. All other portions ofeach straight section include the material of the bushing 34 and therebyprovide structural and radial integrity for the bushing.

Further, the bushing 34 provides a snug assembly of the stem 36 withinthe housing 32 to minimize the wobbling of the stem within the housingand thereby provide an anti-wobbling effect. Consequently, the user of afaucet which includes the valve assembly 30 experiences a secure,non-wobble feeling when turning the stem 34 within the housing 32, and asmooth and user-friendly turning enhanced by the lubricant which isallowed to locate on each side of the cylinder 232 of the bushing 34.

When a riser-type valve is used in a two-handle faucet, the stem of thevalve is rotated to move the stem axially to control the flow of hotwater into the faucet. When the hot-water valve is open, the stem isturned in a clockwise direction to move the stem axially to close thevalve. When the riser-type valve is used to control the flow of coldwater, the stem of the cold-water valve which is open is turned in acounterclockwise direction to move the stem axially to close the valve.This process establishes a "turning convention" which is well known byusers of such valves.

In a non-riser type valve, such as valve assembly 30, the stem of thevalve does not move axially but is rotatable to open and close the valveby operation of a lever handle 270 (FIG. 2) or a non-lever knob handle272 (FIG. 3), such as a cross handle or a round -handle, all of whichare assembled with the splines 110 of the stem 36. In order to maintainthe above-noted turning convention when using the lever handle 270, thevalve assembly 30 can be selectively adjusted during assembly and/orinstallation such that the stem 36 can be turned clockwise to close thevalve associated with the hot water and can be turned counterclockwiseto close the valve associated with the cold water.

The stop wall 64, and the stop surfaces 68 and 70, function inconjunction with the projection 246 to limit the rotational movement ofthe stem 36 to one-half of a full turn. When the valve assembly 30 is tobe used with the lever handle 270 to control the supply of hot water,the stop 40 must be located such that the sidewall 250 of the projection246 is in engagement with the stop surface 70 when the valve assembly isin the closed position. This is accomplished by rotating the stem 36without the stop 40 or the lever 270 in assembly therewith and viewingthe bottom of the valve assembly 30 to determine when the movable disk44 has been positioned to allow the fixed disk 46 to cover the passage164 of the movable disk. At this position, the stop 40 is positionedspatially from the top surface 109 of the stem 36 so that the grooves256 and 258 are facing away from the stem as an indication that the stopis in position for assembly for controlling a hot water valve assembly.In addition, the wide spline 266 of the stop 40 is properly aligned withthe wide space 103 of the stem 36 so that, when the stop is assembledwith the stem, the sidewall 250 of the projection 246 is located inengagement with the stop surface 70.

When the valve assembly 30 which includes the lever 270 is used tocontrol the supply of cold water, the stop 40 is assembled with the stem36 with the grooves 256 and 258 of the stop facing inward of the housing32 and interfaces with the upper surface 66 thereof. In this instance,the stop surface 250 is placed in engagement with stop surface 68 of thestop wall 64 when the valve assembly 30 is in the closed position.

Thus, when the lever 270 is used to control the supply of hot waterthrough the valve assembly 30, the grooves 256 and 258 will face outwardfrom the valve assembly, and will face inward of the valve assembly whencontrolling the supply of cold water through the valve assembly. Whenthe knob handle 272 is used instead of a lever handle 270 to control thesupply of hot or cold water, the turning convention noted above does nothave to be utilized. Therefore, the stop 40 can be assembled in eitherof the two orientations noted above. As a matter of course, when thevalve assembly 30 is destined for assembly with the knob handle 272, thegrooves 256 and 258 face outward from the valve assembly 30 for both thehot and cold supply valve assemblies.

The design of the stop 40 for use in the valve assembly 30, as describedabove, provides for the efficient assembly of the stop at themanufacturing site and also provides for a simple adjustment at theinstallation site, prior to assembly, in the event that the stop is notoriented properly for the selected hot or cold water-control use. Evenafter installation, the lever handle 270 or the knob handle 272 can beremoved from the stem 36 and the stop 40 can be directly accessed foradjustment without dismantling any other elements of the valve assembly30.

Referring to FIG. 28, a portion of the movable disk 44 is illustratedwith various dimensions in inches to reveal the precise configuration ofthe preferred embodiment of the passage 164. While only one-half of thepassage 164 is shown in FIG. 28, the other half of the passage 164 is amirror image of the illustrated portion. The full view of the passage164 is shown in FIG. 12. The portion of the passage 164 shown in FIG. 28is formed by the narrow channel 188 which opens into the much larger bay274 of the passage.

Referring to FIG. 29, a schematical representation shows the assembledmovable disk 44 and the fixed disk 46 as viewed from the bottom surface216 of the fixed disk. As illustrated, the passage 164 of the movabledisk 44 is covered by the solid portion of the fixed disk 46 to precludethe supplying of water through the passage at a zero-degrees position ofthe movable disk.

As shown in FIG. 30, the movable disk 44 has been moved by thirtydegrees in the clockwise direction whereby a small leading portion ofthe narrow channel 188 of the passage 164 is overlapping the passage 218of the fixed disk 46 to allow a small flow of water to be suppliedthrough the associated valve assembly 30. Referring to FIG. 31, themovable disk 44 has been moved by ninety degrees in a clockwisedirection such that the valve assembly 30 is nearly one-half open. Inthis position, water continues to flow through the narrow channel 188 ofthe movable disk 44 while significantly more water is allowed to flowthrough an uncovered part of the larger portion 274 of the passage 164of the movable disk. Finally, as shown in FIG. 32, the movable disk 44continues to be turned in a clockwise direction until the valve assembly30 is fully open. In this manner, the movable disk 44 has been moved byone-hundred and eighty degrees so that all of the passage 164 of themovable disk 44, including the narrow channels 172 and 188 and thelarger portion 274, overlaps the passage 218 of the fixed disk 46.

It is noted that, if the movable disk 44 was turned in thecounterclockwise position from the zero-degrees position of FIG. 29, thevalve assembly 30 would react in the same manner as described above withrespect to narrow channel 188 except that narrow channel 172 would beuncovered initially.

The following chart illustrates the AREA, in square inches, of theoverlap of the passage 164 of the movable disk 44 with the passage 218of the fixed disk 46 by angular movement, in DEGREES, of the movabledisk in increments of ten degrees between zero degrees and one-hundredand eighty degrees:

    __________________________________________________________________________    DEGREES          AREA   DEGREES                       AREA   DEGREES                                    AREA    __________________________________________________________________________    0.00  0.00   60.00 0.009251                              120.00                                    0.04106    10.00 0.00   70.00 0.014331                              130.00                                    0.04647    20.00 0.000695                 80.00 0.01956                              140.00                                    0.05186    30.00 0.002088                 90.00 0.02486                              150.00                                    0.05634    40.00 0.00376                 100.00                       0.0303 160.00                                    0.05854    50.00 0.00578                 110.00                       0.03559                              170.00                                    0.06066                              180.00                                    0.06588    __________________________________________________________________________

An analysis of the above table reveals that the area of the overlapincreases as the valve assembly 30 is opened from a closed position atzero degrees to a fully opened position at one-hundred and eightydegrees. At the lower degrees positions, the narrow channel 188 is beingmoved into an overlapping position where small areas of the channel areopening gradually. The gradual opening of the passage 164, by virtue ofthe narrow channel 188, develops low but gradually increasing rates ofwater flow through the valve assembly 30. In conventional valveassemblies, undesirable noises such as a water "hammering" effectfrequently occur when the valve is opened quickly. When the movable disk44 is turned in a counterclockwise or a clockwise direction as viewed inFIG. 29, the narrow channels 172 and 188, respectively, facilitate thegradual increase in the rate of water flow even when the movable disc isturned quickly. This structure and action essentially precludes theoccurrence of rapid changes in the rate of water flow and theundesirable noisy water "hammering" effect as the movable disk 44 isbeing opened, even where the movable disk is opened quickly. As themovable disk 44 is being turned so that the larger portion 274 of thepassage 164 of the movable disk 44 begins to overlap with the passage218 of the fixed disk 46, the increasing availability of the largerportion of the passage 164 lessens the opportunity for the noisy water"hammering" effect to occur.

As the larger portion 274 of the passage 164 of the movable disk 44 isuncovered and overlaps with the passage 218 of the fixed disk 46, theflow of water over the linking sections 176 and 186 tend to cause someturbulence of the water which could result in undesirable noise.Referring to FIGS. 15 and 16, the placement of the steps 206 and 208adjacent the linking sections 176 and 186, respectively, face the flowof the water which tends to lessen the turbulence of the water as itenters the passage 164 in the vicinity of the linking sections. As shownin FIG. 16, the steps 206 and 208 are located about 0.025 inch from thebottom surface 162 of the movable disk 44. This structure and thewater-flow reaction lessens the development of the undesirable noise.Referring to FIGS. 17, 18 and 19, the steps 210 and 212 are locatedadjacent the steps 208 and 206, respectively, at a distance of about0.100 inch from the bottom surface 162 of the movable disk 44 andfurther enhance the anti-noise effect in conjunction with the steps 208and 206.

In general, the above-identified embodiments are not to be construed aslimiting the breadth of the present invention. Modifications, and otheralternative constructions, will be apparent which are within the spiritand scope of the invention as defined in the appended claims.

What is claimed is:
 1. A valve assembly, which comprises:a housingformed with an opening extending inward of the housing; a stem having alongitudinal axis mounted within the opening of the housing for freerotation relative thereto; a coupler located within the opening of thehousing and having an axis in alignment with the axis of the stem; thecoupler formed with a first axial end which is coupled to the stem forrotation therewith; the coupler formed with a second axial end having aplurality of radially spaced walls extending in an axial direction fromthe second end to define a plurality of asymmetrically arranged radialspaces therebetween; a first fluid-flow valve element formed with anengagement surface on one side thereof and a plurality of radial fingersarranged in an asymmetrical pattern complementary to the asymmetricalarrangement of the radial spaces of the coupler; the radial fingers ofthe first valve element being located in the radial spaces of thecoupler to facilitate rotational movement of the first valve elementwith stem; and a second fluid-flow valve element fixedly attached withinthe opening of the housing and formed with an engagement surface whichis in engagement with the engagement surface of the first fluid-flowvalve element.
 2. A valve assembly, which comprises:a housing formedwith an opening extending inward of the housing; a stem mounted withinthe opening of the housing for free rotation relative thereto; the stemformed with an end located within the opening; a first fluid-flow valveelement having a first side coupled to the end of the stem for rotationtherewith and formed with a second side having an engagement surface; asecond fluid-flow valve element fixedly attached within the opening ofthe housing and formed with an engagement surface which is in engagementwith the engagement surface of the first fluid-flow valve element; thefirst valve element formed with a passage which extends therethroughfrom the first side to the second side; the passage defined by a pair ofspaced narrow symmetrical channels which communicate with opposite sidesof a large bay located therebetween; each of the narrow channels beingformed with a prescribed width; and the larger bay being formed with awidth which is at least twice the prescribed width.
 3. The valveassembly as set forth in claim 2, wherein the passage is formed by asemi-circular wall on one side thereof the ends of which form an outsidewall portion of each of the spaced narrow channels and the center ofwhich forms an outside wall portion of the bay.
 4. The valve assembly asset forth in claim 3, wherein each of the narrow channels is formed withan inside wall portion closely spaced from the outside wall portionthereof which are joined at a base of the channel with the spaced insideand outside wall portions of each channel widening slightly as thechannel extends from the base thereof to the bay.
 5. The valve assemblyas set forth in claim 4, wherein:the portion of each of the channels atits juncture with the bay forms an open mouth of the channel; and theportion of the valve element which is located inboard of and betweeneach of the inside wall portions of the narrow channels and which isopposite the outside wall portion of the bay is formed with a curvedwall portion which extends away from the outside wall portion andbetween the inside wall portions at the mouth of each channel to definethe perimeter of the bay.
 6. A valve assembly, which comprises:a housingformed with an opening extending inward of the housing; a stem mountedwithin the opening of the housing for free rotation relative thereto;the stem formed with an end located within the opening; a firstfluid-flow valve element having a first side coupled to the end of thestem for rotation therewith and formed with a second side having anengagement surface; a second fluid-flow valve element fixedly attachedwithin the opening of the housing and formed with an engagement surfacewhich is in engagement with the engagement surface of the firstfluid-flow valve element; the first valve element formed with a passagewhich extends therethrough from the first side to the second side; thepassage defined by a pair of spaced narrow symmetrical channels whichcommunicate with opposite sides of a large bay located therebetween; aninner wall portion of the bay being defined in part by a pair of spacedextended convex wall sections; and a pair of steps formed in each of theextended convex wall sections of the inner wall portion of the bayfacing in the same direction as the second side of the first valveelement.
 7. The valve assembly as set forth in claim 2, which furthercomprises:a stop surface formed on the housing adjacent an entrance tothe opening; a stop element assembled on the first end of the stempositioned for engagement with the stop surface of the housing to limitthe turning distance of the stem and the first fluid-flow valve element;and structure formed on the stem and the stop element for removablyretaining the stop element with the stem.
 8. The valve assembly as setforth in claim 2, which further comprises:an enclosure element locatedwithin the opening of the housing between a wall of the opening and atleast a portion of the stem to prevent engagement between the stem andthe housing.
 9. The valve assembly as set forth in claim 7, whichfurther comprises:an enclosure element located within the opening of thehousing between a wall of the opening and at least a portion of the stemto prevent engagement between the stem and the housing.
 10. A valveassembly, which comprises:a housing formed with an opening extendinginward of the housing; a stem mounted within the opening of the housingfor free rotation relative thereto; the stem formed with an end locatedwithin the opening; a first fluid-flow valve element having a first sidecoupled to the end of the stem for rotation therewith and formed with asecond side having an engagement surface; a second fluid-flow valveelement fixedly attached within the opening of the housing and formedwith an engagement surface which is in engagement with the engagementsurface of the first fluid-flow valve element; the first valve elementformed with a passage which extends therethrough from the first side tothe second side; the passage defined by a pair of spaced narrowsymmetrical channels which communicate with opposite sides of a largebay located therebetween; an inner wall portion of the bay being definedin part by a pair of spaced extended convex wall sections; and a stepformed in each of the extended convex wall sections of the inner wallportion of the bay facing in the same direction as the second side ofthe first valve element.
 11. A valve assembly, which comprises:a housingformed with an opening extending inward of the housing; a stem mountedwithin the opening of the housing for free rotation relative thereto;the stem formed with an end located within the opening; a firstfluid-flow valve element having a first side coupled to the end of thestem for rotation therewith and formed with a second side having anengagement surface; a second fluid-flow valve element fixedly attachedwithin the opening of the housing and formed with an engagement surfacewhich is in engagement with the engagement surface of the firstfluid-flow valve element; the first valve element formed with a passagewhich extends therethrough from the first side to the second side; thepassage defined by a pair of spaced narrow symmetrical channels whichcommunicate with opposite sides of a large bay located therebetween; anda curved wall portion of the bay defined by a central concave wallsection and a pair of extended convex wall sections which extend fromopposite ends of the concave wall section to respective ones of theinside wall portions of the pair of channels.
 12. The valve assembly asset forth in claim 11, which further comprises:a step formed in each ofthe extended convex wall sections of the curved wall portion of the bayfacing in the same direction as the second side of the first valveelement.
 13. The valve assembly as set forth in claim 11, which furthercomprises:a pair of steps formed in each of the extended convex wallsections of the curved wall portion of the bay facing in the samedirection as the second side of the first valve element.
 14. The valveassembly as set forth in claim 11, wherein the passage is symmetricalabout a line which bisects the concave wall section of the bay.